1. Field of the Invention
The invention relates to a memory and an operating method thereof. More particularly, the invention relates to an antifuse OTP memory cell with performance improvement and an operating method of a memory.
2. Description of Related Art
A non-volatile memory is a type of memory that retains information it stores even when the power supply is cut off. The non-volatile memory may be classified into a read-only memory (ROM), a one-time programmable memory (OTP memory), and a rewritable memory. Moreover, the semiconductor memory technology has progressed to the point where the non-volatile memory can be implemented with the same process as a complementary metal oxide semiconductor (CMOS) device.
The OTP memory described above may be classified into a fuse type and an anti-fuse type. The fuse type OTP memory is short before being programmed and open after being programmed. On the contrary, the anti-fuse type OTP memory is open before being programmed and short after being programmed. Moreover, based on the characteristics of the metal-oxide semiconductor (MOS) device in CMOS fabrication process, the anti-fuse OTP memory is more suitable to be implemented with the CMOS fabrication process.
Moreover, the OTP memory unit forms a permanent conductive path on the ruptured gate oxide layer. Furthermore, the forming location of the permanent conductive path changes with variations in the fabrication process. Therefore, operating methods of the OTP memory unit usually result in erroneous judgments due to different forming locations of the conductive path.